Under-reaming tool



Feb. 16, 1960 w, E, CRAMER 2,924,999

UNDERREAMING TOOL Filed March 11 1955 United States P UNDER-REAMING TOOL Walter E. Cramer; Los Angeles, Calif.

Application March 11, 1955, Serial No. 493,715

1 Claim. (Cl. 77-2) This invention relates to an. under-reaming tool and has as its primary object the, provision of a tool for cutting internal ringrgrooves in the side wall of a counterbore formed in the cylinder; heads of, engines for; the,-

reception of areplacement valve seat.

Another object is to provide a tool for the purposeabove stated of the type embodying an under-reaming cutter on a slide block urged into operative engagement with the work by the wedge action of a screw-fed thrust member, in which the tool is so formed as to accumulate the cuttings being developed by the cutter in a manner to prevent the cuttings from falling or otherwise de- Y I i the c lind h a Aparticular advantage of the invention is that it enables ready reconditioning the cylinder heads of engine blocks by the removal and replacement of worn, warped, pitted or cracked valve-seats by the simple expedient of completely cutting away the original valve seat formed integral with the" head and replacing it with a new seat formed on an insert, the invention contemplating forming the wall of the insert receiving counterbore with a con tinuous peripheral channel for the reception of a splitring whereby the valve seat insert may be locked in place.

A further object is to provide a construction and arrangement in an under-reaming tool of the above character and for the purpose specified whereby accurate spacing of the ring groove formed thereby relative to the bottom of a recess is attained by utilizing the cutting element per se in bottoming the tool in the recess and thereby providing a constant guide for the reamer.

With the foregoing objects in view together with such other objects and advantages as may subsequently appear, the invention resides in the parts and in the combination, construction and arrangement of parts hereinafter described and claimed, and as illustrated by way of example in the accompanying drawing in which:

Fig. 1 is a detail in section of a fragmentary portion of a cylinder head showing the manner of adapting it to be equipped with a valve-seat insert by use of the invention:

Fig. 2 is a view of the tool as seen in side elevation and showing in dotted lines the portion of a cylinder head to which the tool is applied:

Fig. 3 is a plan view ofthe tool:

Fig. 4 is an enlarged vertical section taken on the line 4-4 of Fig. 3:

Fig. 5 is an inverted plan view of the tool:

Fig. 6 is a detail in section taken on the line 6--6 of Fig. 4: and

Fig. 7 is an isometric view of a cutter slide block as removed.

Referring to the drawing more specifically A indicates generally the tool body which embodies a cylindrical end portion 8 and has an internally threaded axial bore 9 having one end terminating in a divergent socket 16 opening through the underside of the end portion 8. A threaded shaft B screwed in the bore 9 is formed at one end with a conical spreader C normally disposed in the socket 10. An elongated cylindrical stem 11 projects axially from the underside of the spreader C. The

upper end ofthe threaded shaft B projects from the upper. end of the body A andhas a hand wheel D fixed thereon,' the hand wheel being screwed on the shaft B and secured in place by a set screw 12 carried by the wheel D and engaging a longitudinal channel a in the shaft B.

In carrying out the invention the body A is formed at the base of the end portion A with a circumferential wall b of the channel E. Mounted in the channels: F-E are cutting elements embodying slide blocks G, G formed with longitudinal side ribs 040 which slidably engage grooves dd in the side walls of the channelsv The inner ends e of the slide blocks GG are inclined and are presented to the opposite sides of the conical spreader C. The lower portions of the outer ends of the slide blocks G G are curved transversely to conform to the curvature of the perimeter of the end portion 8, while the upper portions of the outer ends of the slide blocks are inset and are arcuate as indicated at f and conform to the bottom wall b of the channel B when the slide blocks are in their innermost retracted position as shown in Fig. 5. The, slide blocks, are normally maintained in such innermost position by a taut elastic band or garter spring g positioned in the channel E and which overlies and abuts the inset outer end portions of the slide blocks. Thespring g is preferably formed of coiled spring wire placed under tension when the spring is seated in the channel E so as to exert an inward pull on the blocks and yieldably oppose outward movement thereof.

Each of the slide blocks G G is formed on its outer end with a protruding reamer 14 of arcuate cross section adapted when brought to bear against a surface being worked and advanced along such surface as by rotation of the body A, to cut a groove in the surface, and extending from the leading end of the reamer is a shallow or clearance recess formed with an upwardly and inwardly inclined bottom wall 15 leading to a fiat ledge 16 the surface of which extends on a plane with the lower side wall of the channel E.

The wall 15 serves to direct the shaving formed by the reamer into the channel E.

The undersides of the slide blocks G--G are flat faced as is the underside of the end portion 8 of the tool body A, and the undersides of the blocks GG are exposed throughout at the lower end of the tool body A and are formed and arranged to extend on the plane of the underside of the tool body A or at least substantially so, it being desirable that the end portion 8 does not project beyond the underside of the slide blocks.

While the tool body A maybe rotated in any suitable fashion it is here shown as equipped with aligned horizontally extending handles H-H aliixed to and projecting from opposite sides of the upper portion of the body A whereby the latter may be manually turned.

Prerequisite to the use of. the above described tool, a cylinder head I to be worked is conditioned by cutting out the damaged valve seat and in so doing forming an annular recess K in the surface of the head having a flat bottom wall It and a cylindrical side wall i, for the reception of a replacement valve seat ring L as shown in Fig. 1. Having formed the recess K a subject tool having an end portion 8 sized to slidably conform to the wall 1' is applied by inserting the stem 11 in the valvestem guideway j of the cylinder head I as indicated in dotted lines in Fig. 1, and the end portion 8 is positioned in the recess K with the flat undersides of the slide blocks or cutting elements GG seated on the bottom Patented Feb, 1 959 wall h of the recess K. The shaftB is then rotated by means of the hand wheel D to advance the shaft in the body A so as to cause the conical spreader C to engage the inner ends of the slide blocks GG and then thrust the latter outwardly in opposition to the spring to dispose the reamers 14 into cutting engagement with the wall 1'. On this being accomplished the body A is rotated to cause the reamers 14 to cut a peripherial groove k around the wall 1', the blocks GG being advanced from time to time by manipulation of the hand wheel D to deepen the cut of the reamers until the groove is formed of requisite depth to receive a split locking ring I applied in a registering groove m in the periphery of the valve seat ring L. By seating the undersides of slide blocks GG on the bottom wall h of the recess K such bottom wall serves as a constant guide for the reamer 14 so that the latter'will form the groove k in accurately spaced relation to the bottom wall h.

On completion of the reaming operation, the shaft B is rotated to fully retract the spreader C whereupon the elastic band will function to retract the slide blocks GG and thereby withdraw the reamers 14-14 from engagement with the cut groove k. The tool is then removed and-the valve seat ring L set in place. I

While a Specific embodiment of the invention has been shown and described, the invention is not limited to the exact details of construction set forth, and the invention embraces such changes, modifications and equivalents of the parts and their formation and arrangement as come within the purview of the appended claim.

I claim:

A tool for cutting a ring groove in the inner perimeter of the side wall of a cylindrical recess, a body having a cylindrical end portion slidably conformable to said side wall, a pair of slide blocks mounted in said body for reciprocable movement transversely thereof having outer end portions adjacent the periphery of said end portion, reamers on said outer end portions cngageable with the side wall of the recess, means for thrusting said slide blocks outwardly, a garter spring for urging said slide blocks inwardly, said body being formed with a peripheral channel having an arcuate bottom wall in which said spring is seated and spaced inwardly from the periphery of said body, said slide blocks having inset wall portions on their outer ends conformable to said arcuate bottom wall engaged by said spring and having marginal ledges aligned with a side wall of said channel, and said slide blocks having shallow recesses in their outer end walls'at the'leading ends of said reamers formed with upwardly and inwardly inclined bottom walls leading to said ledges for directing cuttings from said reamers toward and into said peripherial channel.

7 References Cited in the file of this patent UNITED STATES PATENTS 1,528,653 

